Transient-enhanced Diffusion Of Iridium And Its Eflects On Electrical Characteristics Of Deep Sub-micron nMOSFETs

Abstract

ABSTRACT RESULTS and DISCUSSION Accurate 2D doping profiles are needed to simulate shortFig. 2 shows measured C-V curves and simulations fits for channel nMOSFETs with indium channel. BY combining a lOOpm x 100pm nMOSFET. Excellent fit was established indium transient-enhanced diffusion (TED), segregation, and thoughout the C v curves for the 1D case. The kink near quantum mechanical (OM) effects, c V curves measured on the flat-band part of the C-V curve is due to the high nMOSFETs with various gate lengths can be simulated ionization energy (0.16 eV) of indium [5], and is confirmed accurately. Although indium exhibits severe TED, the by measuring C-V curves at various temperatures (Fig. 3). reverse-short-channel effect (RSCE) is reduced due to the for an indium-doped 0.2 strong segregation of indium into the gate oxide. In addition, gate n ~ ~ ~ ~ ~ ~ . B~ combining the effect of TED diffusion experiments using a buried indium marker layer on indium with the experimentally observed strong confirms that indium has severe TED, similar to boron, segregation into the gate oxide [6 ] , the 2D indium profile can which can be reduced by using an RTA after an implant. be accurately captured and the fit of the C-V curves is excellent. Fig. 5 shows the change in doping contours with candidate for achieving a retrograde and without considering indium TED and segregation effects. profile (RCP) in deep sub-micron ~ O S F E T ~ [I] , TED pushes indium towards the surface because of point H ~ ~ ~ ~ ~ ~ , transient-edanced difhsion (TED) due to ion defect gradients and reduces the peak indium concentration. implantation damage can excessive dopant diffusion In addition, the TED of indium allows indium to reach the which severely affects MOSFET~ characteristics [21, Until heavily doped source/drain regions by electric field assisted now, little has been reported on how the TED of indium dif is ion where indium is trapped in the highly doped n-type affects redistribution of the channel dopant profile. In this region. Due to the strong segregation of indium into the gate work, a C-V technique was used to obtain detailed 213 indium oxide, the amount of indium pileup near the surface is channel profiles, and a TED model for indium was extracted reduced, and consequently, the RSCE in an indium channel [3]. Diffusion experiments based on buried indium marker device is smaller compared to a boron channel device as layer were used to monitor the TED of indium due to ion shown in Fig. 6. implantation damage. ~ i ~ . 4 shows the C-V